This application is based on and claims the priority under 35 U.S.C. xc2xa7119 of German Patent Application 100 14 500.0, filed on Mar. 23, 2000, the entire disclosure of which is incorporated herein by reference.
The invention relates to an electrical outlet or receptacle with a protective cover that is slidable to selectively cover or uncover the electrical contact socket openings of the electrical outlet, into which the electrical contact pins of a mating electrical plug may be inserted for establishing an electrical connection. This electrical outlet is particularly suitable for use in an aircraft, and is to be arranged close to a passenger seat in an aircraft, for providing electrical power to portable electrical and electronic devices such as laptop computers, compact disk and cassette tape players, and the like.
Due to the ever expanding availability and use of portable electrical and electronic devices, such as laptop computers, compact disk players, cassette tape players, and the like, there has been an increasing demand by passengers to also use such devices during flight in an aircraft. Since the battery or accumulator capacity of such devices is not sufficient for powering the devices during longer flight durations, there is further a demand for electrical outlets arranged in or near passenger seats in an aircraft, in order to provide electrical power for powering such passenger convenience devices. However, in view of the dangers of electromagnetic interference in an aircraft and for various other reasons, it is not possible, i.e. it is not allowed, for passengers to operate any desired electrical or electronic device.
In order to control the types of electronic devices that may be plugged into electrical outlets provided for passenger use in the aircraft, regulations specify the type or functional features of electrical outlets that may be provided in an aircraft. In this context, an electrical outlet is required, into which typical commercially available electrical plugs will not fit without a special adapter. This prevents a passenger from plugging an electrical device into the electrical outlet unless the passenger has been provided with the special adapter. Such an adapter must fulfill the following requirements. The adapter must provide the possibility of connecting to a hypertronic electrical outlet with a 15 volt d.c. outlet voltage. Also, the adapter must be able to deliver or derive the necessary supply voltage required by a laptop computer or the like, from the 15 volt d.c. voltage that is available from the outlet. Also, the adapter must provide the specific configuration of the electrical contact socket openings to mate with the respective electrical plug of the laptop computer or the like.
It is a disadvantage of using such adapters, that it becomes necessary to constantly develop and provide new adapters for aircraft applications, necessitated by the rather rapid changing of models and electrical connection requirements of various electrical and electronic devices such as laptop computers and the like. As a result, it becomes an ongoing burden to provide updated adapters. Moreover, the availability of a suitable adapter is not always ensured, so that a passenger will not necessarily be able to use the intended electrical or electronic device in the aircraft. A further disadvantage is that the necessary adapters are not provided by the manufacturers of the laptop computers or other devices, so that a suitable compatibility between the laptop computer or other device and the aircraft electrical outlets is not always ensured.
It is also generally known in the art to provide an electrical outlet with a protective cover that selectively closes or opens the electrical contact socket openings, so as to selectively allow or prevent the contact pins of an electrical plug to be inserted into the socket openings of the electrical outlet. Generally, such a protective cover is slidable in a direction perpendicular to the axis of the electrical outlet, and includes a sloping surface or the like, so that the contact pins of an electrical plug being inserted into the socket openings will cause the protective cover to be pushed slidingly aside, so as to allow the contact pins to be inserted into the socket openings and thereby establish an electrical connection. Such an electrical outlet may further include a locking or latching mechanism that selectively prevents the protective cover from being pushed slidingly out of its position covering the socket openings. Special measures must be carried out in order to unlatch the latching mechanism.
More particularly, a variety of different electrical outlet configurations or structures have become known in this context. For example, published British Patent Specification GB 612,486 discloses an electrical outlet that includes a protective mechanism for covering the electrical contact socket openings thereof, in the form of two flat insulating plates. These insulating plates are generally urged and held into a rest position by one or two compression springs, particularly by the influence of the springs respectively pressing against a protrusion of each respective insulating plate. In this resting position, the insulating plates are in a pivoted position in which they are blocked from sliding in a direction necessary for uncovering the socket openings. By inserting the ground contact pin of an electrical plug into a corresponding opening of the electrical outlet, this grounding contact pin of the plug causes the insulating plates to pivot into an unlocked or unblocked position. Then, as the electrical plug is inserted further into the electrical outlet, the conductor pins being inserted into the corresponding socket openings cause the insulating plates to slide into a further position in which they open or uncover the corresponding socket contacts of the electrical outlet.
Published European Patent Application EP 0,539,093 discloses an electrical outlet with two contacts for connecting with the pin contacts of an electrical plug. The electrical outlet includes a shutter element which covers two socket openings provided in the front face wall of the electrical outlet, when this shutter element is in a closed position. Also, the shutter element is latched in this closed position, i.e. is prevented from sliding out of the closed position into an open position in which the socket openings are uncovered. The shutter element is unlatched by the insertion of the ground contact pin or a protrusion of the electrical plug. Particularly, the ground contact pin spreads apart two latching legs of the shutter element, so as to disengage these latching legs from a fixed latching element. Then, the insertion of the electrical contact pins of the electrical plug into the corresponding socket openings of the electrical outlet causes the shutter element to slide out of the way, to allow the contact pins to enter into the socket contacts of the electrical outlet in order to establish the electrical connection therebetween.
German Utility Model DE 92 11 368 U1 discloses a safety contact plug connector or electrical outlet including an electrical plug and a housing that is closeable or coverable by a cap. The housing includes a base body made of an electrically insulating material, with shielding contacts as well as two contact sleeves or sockets for respectively receiving the contact pins of a profiled electrical plug. The plug can be inserted into an appropriately formed recess of the cap. The floor of this recess is provided with holes through which the contact pins of the plug are inserted. An essentially T-shaped blocking element is rotatably arranged between the floor of this recess and the free ends of the contact sleeves in the housing. The T-shaped blocking element is biased by a spring to rotate into a blocking position. A flange of the blocking element protrudes into the space between the two holes in the floor of the recess and the free ends of the contact sleeves. An unlatching pin is arranged on the electrical plug. When the plug is inserted into the recess, this unlatching pin passes through an unlatching hole in the floor of the recess and then bears on or acts on an adjusting surface on a web of the blocking element. Thereby, the blocking element is moved or particularly rotated against the pre-biasing spring forces, and the flange of the blocking element uncovers the space between the floor of the recess and the free ends of the contact sleeves, so that the contact pins of the plug can be inserted into the contact sleeves.
Published European Patent Publication EP 0,763,875 A1 discloses an electrical plug connection including an electrical plug and an electrical outlet. The openings of the plug contact sockets are usually covered by a surfacially extending or plate-shaped closure element that is slidably arranged in the housing of the electrical outlet. An adapter fitted onto the electrical plug serves to move the closure element so as to open the socket openings for the purpose of inserting the contact pins of the electrical plug into the plug contact sockets of the electrical outlet. For this purpose, the adapter includes an unlocking or unlatching pin, which cooperates with the slidable closure element upon inserting the plug into the outlet, in order to achieve a sliding displacement of the closure element and thereby to uncover or open the socket openings of the contact sockets. Particularly, the unlatching pin of the adapter presses down on a flexible latch member of the closure element, so as to be moved clear of a fixed latching element, and thereby allow the closure element to be slidingly displaced by the contact pins of the plug being inserted into the corresponding socket openings. Thereby, it becomes possible to insert the pin contacts of the electrical plug into the socket contacts of the electrical outlet so as to establish the electrical connection therebetween.
Published European Patent Application EP 0,646,990 A1 discloses an electrical outlet that includes a closure element that selectively covers the socket openings of the socket contacts. Upon insertion of an electrical plug into the electrical outlet, the closure element is slidable in a direction perpendicular to the axis of the electrical outlet, and particularly in a prescribed direction, so as to selectively open or uncover the socket openings. The closure element is biased to slide into the closed position by the spring force of a compression spring. The closure element is usually also locked or latched into this closed position. An adapter is provided on the electrical plug, whereby the adapter has two unlatching pins that are inserted into corresponding holes in the housing, in order to unlatch the closure element. In this arrangement, it is disadvantageous, that the adapter must be arranged onto the electrical plug each time before being able to establish the electrical connection, i.e. before being able to insert the electrical plug into the electrical outlet. Also, the adapter must be exactly properly positioned on the electrical plug in order that the unlatching pins will be properly guided into the corresponding openings for the purpose of unlatching the closure element, while the contact pins are inserted into the socket openings. Also the latching mechanism is rather complex.
In view of the above it is an object of the invention to provide a safety electrical outlet including a protective cover of the above described general type, which is especially configured so that an electronic or electrical device can be easily plugged into the electrical outlet using the standard power cable and associated electrical plug prescribed by the manufacturer of the device, without requiring any special complicated measures. Particularly, the inventive electrical outlet shall accept a standard electrical plug without requiring an adapter mounted on the electrical plug. The invention further aims to avoid or overcome the disadvantages of the prior art, and to achieve additional advantages, as apparent from the present specification.
The above objects have been achieved according to the invention in an electrical outlet including a housing that comprises a receptacle housing having socket openings therein, and a housing block with socket contacts therein, whereby the contact pins of an electrical plug may be inserted through the socket openings to engage into and make contact with the socket contacts. The electrical outlet further includes a closure element slidably arranged in the housing block so as to be slidable substantially perpendicularly to the insertion axis between a first position in which it covers or closes the socket openings (or rather blocks respective insertion paths extending from the socket openings to the socket contacts), and a second position in which it uncovers or opens the socket openings. The closure element includes sloping surfaces, which are pressed against by the contact pins of the electrical plug as the plug is inserted, so that the sloping surfaces cause a lateral force to be applied to the closure element, causing the closure element to slide from the closed position to the open position.
Further according to the invention, a mechanism is provided for latching the closure element in the closed position, to prevent the closure element from sliding into the open position. The latching mechanism includes a latching element comprising a latching pawl connected to a mounting element by a connector web. The latching element, or at least the latching pawl thereof, is displaceable in a direction substantially parallel to the plug insertion axis of the electrical outlet. The latching pawl is ordinarily urged by a spring into a latching position, in which the latching pawl engages the closure element so as to prevent the closure element from sliding from the closed position into the open position. By displacing the latching pawl in a direction against the spring bias force substantially parallel to the insertion axis, the latching pawl is disengaged from the closure element so that the closure element can slidingly move from the closed position into the open position.
The entire latching element may be slidably received in the housing block, so that the entire latching element may slide parallel to the insertion axis for latching or unlatching the closure element. However, preferably, the mounting element of the latching element is fixed in the housing block, e.g. press-fit into a groove extending parallel to the insertion axis in the housing block, and the connector web and/or the latching pawl are elastically flexible, so that the latching pawl may be flexibly deflected in a direction parallel to the insertion axis, for selectively latching or unlatching the closure element.
The inventive arrangement or combination preferably further includes an adapter that is fitted on the electrical outlet. Particularly, the adapter includes an adapter body that is pressed against the floor surface of the receptacle recess of the electrical outlet, as well as an unlatching pin that protrudes from the adapter body and is inserted into the electrical outlet housing so as to exert an axial force against the latching element and particularly the connector web or the latching pawl thereof in a direction parallel to the insertion axis. In this manner, the adapter and particularly the unlatching pin thereof displaces the latching pawl in the insertion axis direction so as to disengage the latching pawl from the closure element. Then, when the contact pins of an ordinary electrical plug are inserted through corresponding holes in the adapter and into the socket openings of the electrical outlet, the contact pins will press against the sloping surfaces of the closure element and cause the closure element to slide from the closed position into the open position. Then, further insertion of the contact pins of the electrical plug will bring the contact pins into electrically contacting engagement with the socket contacts.
According to further particular details of the invention, the closure element includes an elongated guide body and two closure arms or legs arranged laterally and longitudinally relative to the elongated guide body. The sloping surfaces are respectively provided on the closure arms. The elongated guide body is slidingly received in a groove in the housing block or the receptacle housing and is, for example, biased into the closed position by a compression spring. The elongated guide body further includes a latch recess, latch opening or latch protrusion that is configured and adapted to be engaged by the latching pawl of the latching element.
Alternatively, the closure element and the latching element may have any respective configurations that achieve the general features of the invention.
An advantage of the invention is that the electrical outlet remains xe2x80x9clockedxe2x80x9d, i.e. an electrical plug cannot be inserted in the electrical outlet, unless the adapter has been inserted into the electrical outlet. Thus, the adapter essentially serves the function of a key that unlocks the electrical outlet to make it available for use. Once the adapter has been inserted into the electrical outlet, then a conventional electrical plug can be inserted into the electrical outlet, whereby the contact pins thereof cause the closure element to be slidingly moved from the closed position to the open position, so that the contact pins can be further inserted to make a contact connection with the socket contact elements of the electrical outlet. The closure element prevents accidental or passing insertion of other items into the electrical outlet, even if the adapter has been inserted to xe2x80x9cunlockxe2x80x9d the outlet.
Since the adapter is allocated to and inserted in the electrical outlet (rather than being mounted on the electrical plug), this combination of the adapter and the electrical outlet ensures that an electrical plug can be plugged into the electrical outlet in a routine manner, without requiring special measures to be taken by the passenger or other user of the electronic or electrical device that is to be plugged in. Particularly, there is no need for the user of the device to first attach an adapter onto the electrical plug of his electrical or electronic device. To the user, the arrangement of the adapter on the electrical outlet is essentially xe2x80x9ctransparentxe2x80x9d and not troublesome or conspicuous, and the user must simply plug his electrical plug into the electrical sockets in the ordinary manner.
A further advantage of the inventive arrangement is that it achieves the intended purposes with a rather simple structural arrangement of simple components, which carry out their functions directly by sliding and/or deflecting, and without requiring complicated pivoting or compound motions.